In a manufacturing process of a semiconductor device or a liquid crystal display, there is used a single-substrate-processing apparatus processing a substrate one by one to perform a processing liquid treatment on a main surface of a substrate such as a semiconductor wafer and a glass substrate for a liquid crystal display panel. A single-substrate-processing apparatus comprises, for example, a spin chuck rotating a substrate while retaining the substrate in a generally horizontal position, and a center axis nozzle supplying a processing liquid to a lower surface of the substrate retained by the spin chuck.
For example, following Patent document 1 discloses a substrate processing apparatus comprising a lower surface processing piping having a lower surface dispense port for supplying a processing liquid to a lower surface of a substrate held by a spin chuck and a disk-shaped opposed plate arranged in an opposed manner to the lower surface of the substrate. In a state where the opposed plate is arranged in an approximate position where the opposed plate approximates the lower surface of the substrate, the processing liquid is dispensed from the lower surface dispense port. As a result, the processing liquid is retained in a liquid-tight state between the lower surface of the substrate and a substrate opposed surface of the opposed plate.